Delivered Before the Legislature at Sacramento, Thursday Evening, January 30th, 1868: to which are Appended: Two Letters to the Governor Relative to the Progress of the Geological Survey Communicated to the Legislatures of 1865-6 and 1867-8; Also, the Report of the Commissioners to Manage the Yosemite Valley and the Mariposa Big Tree Grove, for the Years 1867-8[?]